Chapter 18: Biodiversity, Classification And Conservation Flashcards
What is a species?
A species is a group of organisms with similar
morphology and physiology, which can breed together to produce fertile offspring and are reproductively isolated from other species.
What is an ecosystem?
An ecosystem is a relatively self-contained, interacting community of organisms, and the environment in which
they live and with which they interact.
What is a habitat?
A habitat describes the place where a species lives
within an ecosystem.
What is a niche?
A niche is the role of an organism in an ecosystem.
What is biodiversity?
The variety of species in an area along with
their variation within species and the genetic diversity between them.
What are the three levels of diversity?
■ the variation in ecosystems or habitats
■ the number of different species in the ecosystem and their relative abundance
■ the genetic variation within each species
What is species richness?
The number of species in a community is known as
species richness
What is species diversity?
Species diversity takes species richness into
account, but also includes a measure of the evenness of the abundance of the different species. The more species there are, and the more evenly the number of organisms are distributed among the different species, the greater the species diversity
Why is species diversity important?
Species diversity is considered important because ecosystems with high species diversity tend to be more stable than ones with limited diversity; they are more able to resist changes.
What is genetic diversity?
Genetic diversity is the diversity of alleles within the genes in the genome of a single species.
How is genetic diversity assessed?
Genetic diversity within a species can be assessed by finding out what proportion of genes have different alleles and how many alleles there are per gene.
How is random sampling using quadrats carried out?
A quadrat is a square frame that marks off an area of
ground, or water, where you can identify the different species present and/or take a measurement of their
abundance.
Samples are taken randomly eg by using random number generator to give coordinates of sampling points in the area to avoid any bias and increase accuracy of estimate.
Random sampling is used when an area looks reasonably uniform and there is no clear pattern to the way species are distributed.
How can you use the data from random sampling using quadrats?
There are two ways to use the results:
o Species frequency: is the measure of the chance of a
particular species being found in any one quadrant.
𝑁𝑜. 𝑜𝑓 𝐴𝑝𝑝𝑒𝑎𝑟𝑎𝑛𝑐𝑒/
𝑁𝑜. 𝑜𝑓 𝑄𝑢𝑎𝑑𝑟𝑎𝑡𝑠 × 100
o Species density: is a measure of how many individuals there are per unit area.
𝑇𝑜𝑡𝑎𝑙 𝑁𝑜. 𝑜𝑓 𝑖𝑛𝑑𝑖𝑣𝑖𝑑𝑢𝑎𝑙𝑠 𝐶𝑎𝑙𝑐𝑢𝑙𝑎𝑡𝑒𝑑/
𝑇𝑜𝑡𝑎𝑙 𝐴𝑟𝑒𝑎 𝑜𝑓 𝐴𝑙𝑙 𝑄𝑢𝑎𝑑𝑟𝑎𝑡𝑠
Units: m-2
▪ When unable to count, use percentage cover
1) Divide eg 100 x 100 cm quadrat to 100 small
squares
2) Decide approx. what % area inside quadrat is
occupied by each species using the Braun-Blanquet cover scale.
What is the mark-release-recapture technique?
o As many individuals possible are caught
o Each individual is marked in a way that would not
affect its chance of survival or reproduction
o The marked individuals are counted and returned to
their habitat to mix randomly with the rest of the population.
o After enough time elapses for mixing to take place, another large sample is captured. The number
of marked and unmarked individuals is counted. The
proportion of marked to unmarked individuals is then
used to calculate an estimate of the total number in the population.
𝑁 = (𝑛1 × 𝑛2)/𝑚2
N = population estimate
n1 = number of marked individuals released
n2 = total number of individuals (both marked and
unmarked) captured
m2 = number of marked individuals recaptured
What does the Simpson’s index of diversity calculate?
Using the results about the abundance of the species in a particular area, using this calculation, a value can be given for the species diversity in that area.
What is an advantage of using Simpson’s index of diversity?
Organisms do not have to be identified to use this method.
What is the formula for Simpson’s index of diversity?
𝐷 = 1 − 𝛴 [(n/N)^2]
where n is the total number of organisms of a particular species, and N is the number of all species
What does the Simpson’s index of diversity value D indicate?
Values of D range from 0 to 1. A value near 0 represents a very low species diversity. A value near 1 represents a very high species diversity.
When is systematic sampling carried out?
It is used to determine species distribution in areas where conditions such as altitude, soil moisture content, pH or exposure to light intensity varies.
What is a transect and what are the two types of systematic sampling carried out?
A starting point is selected in the field and a line known as a transect is laid out in the area in a straight line.
Transects are used to detect changes in community composition along a line across one or more habitats.
• Line transect
The number of organisms found at regular points along
a line are noted.
• Belt transect
The abundance of organisms within quadrats placed at regular intervals
Data from a line transect can be shown as a drawing. Data from a belt transect can be plotted as a set of bar charts or as a kite diagram
When can you have the strongest correlation?
When all the points in a scatter graph lie on the same line.
When can Pearson’s correlation coefficient be used?
It can only be used when there is a visible linear correlation and when quantitative data has been collected as measurements or counts. The data must be distributed normally(graph does not appear to be skewed or have obvious outliers).
What are correlation coefficients used for?
The correlation coefficients are ways to test a relationship that has been observed and recorded to see if the variables are correlated and, if so, to find the strength of that correlation.
A correlation coefficient of 0 means that there is no correlation at all.
When can Spearman’s rank correlation be used?
It can be used when quantitative data may not have been collected, but used an abundance scale or when its not certain whether the data is normally distributed. It may also be used when the scatter graph shows that the data is correlated but not in a linear fashion.
How is Spearman’s rank correlation found and how is it used?
rs = 1 − [(6 × ∑D^2)/(n^3-n)]
where n is the number of pairs of items in the sample
and D is the difference between each pair of ranked
measurements and ∑ is the ‘sum of’.
A scatter graph can be drawn to see if there is any correlation.
• The closer the value rs is to 1, the more likely it is that
there is a correlation between the two sets of data
• The rs value you calculated is then compared with the
critical value- if rs is greater than the critical value, then null hypothesis is rejected, meaning there is a significant correlation.
How is Pearson’s linear correlation found and used?
This linear correlation graph can be graphed on a scatter graph using the quantitative data as measurements or counts. The formula:
𝑟 =(𝛴𝑥𝑦 − 𝑛𝑥̅𝑦̅)/𝑛S𝑥Sy
𝑛 = sample size (number of observations)
𝑥, 𝑦 = number of species x, number of species y
𝑥̅,̅𝑦= mean
𝑠𝑥, 𝑠𝑦 = standard deviation of x and y
• The value of r is always between -1 and 1, where -1
indicates a negative correlation, 1 indicates positive
correlation, and 0 indicates no correlation.
What is taxonomy?
Taxonomy is the study and practice of classification, which involves placing organisms in a series of taxonomic units or taxa.
What is the hierarchy of classification?
Domain Kingdom Phylum Class Order Family Genus Species
Between which two domain are prokaryotes divided?
Archaea and bacteria
What are the three domains?
Bacteria, archaea and eukarya
What are some characteristics of the Domain Bacteria?
■ They are prokaryotes
■ cells with no nucleus
■ DNA exists as a circular ‘chromosome’ and does not have histone proteins associated with it
■ smaller circular molecules of DNA called plasmids are often present
■ no membrane-bound organelles (such as mitochondria, endoplasmic reticulum, Golgi body, chloroplasts) are present
■ ribosomes (70 S) are smaller than in eukaryotic cells
■ cell wall is always present and contains peptidoglycans (not cellulose)
■ cells divide by binary fission, not by mitosis
■ usually exist as single cells or small groups of cells.
What are some characteristics of the Domain Archaea?
■ They are prokaryotes
■ cells with no membrane-bound organelles
■ DNA exists as a circular ‘chromosome’ and does have histone proteins associated with it
■ smaller circular molecules of DNA called plasmids are often present
■ ribosomes (70 S) are smaller than in eukaryotic cells, but they have features that are similar to those in
eukaryotic ribosomes, not to bacterial ribosomes
■ cell wall always present, but does not contain
peptidoglycans
■ cells divide by binary fission, not by mitosis
■ usually exist as single cells or small groups of cells
■ many inhabit extreme environments
To which domain is the metabolism of archaea similar to?
Bacteria
To which domain is the transcription of domain archaea similar to?
Eukarya
What are some characteristics of the Domain Eukarya?
■ cells with a nucleus and membrane-bound organelles
■ DNA in the nucleus arranged as linear chromosomes with histone proteins
■ ribosomes (80 S) in the cytosol are larger than in
prokaryotes; chloroplasts and mitochondria have 70S
ribosomes, like those in prokaryotes.
■ chloroplast and mitochondrial DNA is circular as
in prokaryotes
■ a great diversity of forms: there are unicellular, colonial and multicellular organisms
■ cell division is by mitosis
■ many different ways of reproducing – asexually
and sexually.
What are the four kingdoms of eukarya?
Protoctista, fungi, plantae, animalia
